License upgrade

Debian puts the Tangerine icon theme in non-free because it falls under the CC-BY-SA 2.5 license. Is there a chance that the license will be upgraded to CC-BY-SA 3.0 so that it can move to main? We would like to base the default theme for gNewSense 3.0 (which is based on Debian) on Tangerine and it would make our job easier if we didn't have to reimport the package.